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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
1
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pubmed:dateCreated |
1987-1-28
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pubmed:abstractText |
Activation of acetyl-CoA carboxylase during incubation of crude extracts of lactating rat mammary gland with Mg2+ and citrate can be blocked by NaF, suggesting that it represents a dephosphorylation of the enzyme. The greater extent of activation in extracts from 24 h-starved rats (200%) compared with fed controls (70%) implies that the decrease in acetyl-CoA carboxylase activity in response to 24 h starvation may involve increased phosphorylation of the enzyme. Acetyl-CoA carboxylase was purified from the mammary glands of lactating rats in the presence of protein phosphatase inhibitors by avidin-Sepharose chromatography. Starvation of the rats for 24 h increased the concentration of citrate giving half-maximal activation by 75%, and decreased the Vmax. of the purified enzyme by 73%. This was associated with an increase in the alkali-labile phosphate content from 3.3 +/- 0.2 to 4.5 +/- 0.4 mol/mol of enzyme subunit. Starvation of lactating rats for 6 h, or short-term insulin deficiency induced by streptozotocin injection, did not effect the kinetic parameters or the phosphate content of acetyl-CoA carboxylase purified from mammary glands. The effects of 24 h starvation on the kinetic parameters and phosphate content of the purified enzyme were completely reversed by re-feeding for only 2.5 h. This effect was blocked if the animals were injected with streptozotocin before re-feeding, suggesting that the increase in plasma insulin that occurs on re-feeding was responsible for the activation of the enzyme. The effects of re-feeding 24 h-starved rats on the kinetic parameters and phosphate content of acetyl-CoA carboxylase could be mimicked by treating enzyme purified from 24 h-starved rats with protein phosphatase-2A in vitro. Our results suggest that, in mammary glands of 24 h-starved lactating rats, insulin brings about a dephosphorylation of acetyl-CoA carboxylase in vivo, which may be at least partly responsible for the reactivation of mammary lipogenesis in response to re-feeding.
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-213055,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-2857659,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-2858203,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-2864919,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-38145,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-4327777,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6108209,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6108241,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6121720,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6122472,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6123311,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6123319,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6126184,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6133873,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6137213,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6143665,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6146523,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6152728,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6232923,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6260494,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6301826,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6303789,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6370233,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6370237,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6373379,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6388568,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-6733262,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-7032513,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2879530-728115
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Jul
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pubmed:issn |
0264-6021
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
1
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pubmed:volume |
237
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
85-91
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:2879530-Acetyl-CoA Carboxylase,
pubmed-meshheading:2879530-Animals,
pubmed-meshheading:2879530-Fatty Acids,
pubmed-meshheading:2879530-Female,
pubmed-meshheading:2879530-Food,
pubmed-meshheading:2879530-Kinetics,
pubmed-meshheading:2879530-Lactation,
pubmed-meshheading:2879530-Ligases,
pubmed-meshheading:2879530-Mammary Glands, Animal,
pubmed-meshheading:2879530-Phosphates,
pubmed-meshheading:2879530-Phosphoprotein Phosphatases,
pubmed-meshheading:2879530-Pregnancy,
pubmed-meshheading:2879530-Protein Phosphatase 2,
pubmed-meshheading:2879530-Rats,
pubmed-meshheading:2879530-Rats, Inbred Strains,
pubmed-meshheading:2879530-Starvation
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pubmed:year |
1986
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pubmed:articleTitle |
The role of acetyl-CoA carboxylase phosphorylation in the control of mammary gland fatty acid synthesis during the starvation and re-feeding of lactating rats.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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